Is this a good opportunity for a new agent?

[John Henry]

I am a new part time agent in a non-metro area. Ive been licensed for about 5 months and havent made any sales. I am part time because I work construction project management full time. A very experience successful builders I work with made me an offer. He proposed opening a brokerage where I am the sole agent. He would rent the building, pay for all marketing, set up IDX website, and show me the ropes. He promised me all the leads he can get on both resell and all his new construction. 

The only potential downside I am seeing is, he asked me to sign a non-compete. If I ever left his brokerage, I would not be able to sell real estate in our area (30 mile radius) for 5 years after leaving. He says its because he has watched every good agent in this area learn from a brokerage, go out on their own, and then become direct competition.

What would you do? My gut tells me to not sign a non-compete, but I also see extreme potential in this opportunity. My goal has been to be an agent that works new construction. How can I negotiate the non-compete to be fair for both of us?